A technique to perform an automatic focusing operation by moving a lens by an electromagnetic force acting against an urging force of a spring member is known as a lens drive method for a camera module incorporated in a small electronic appliance such as a portable telephone (see, for example, Patent Literatures 1 and 2).
A camera module using this kind of lens drive method is provided with a spring member such as a compression coil spring or a plate spring which elastically urges a lens toward an initial position along an optical axis direction, electromagnetic drive means capable of driving the lens along the optical axis direction by producing an electromagnetic force against the urging force of the spring member, the electromagnetic drive means including a coil and a magnet, and control means which moves the lens to a predetermined position by controlling a drive current supplied to the electromagnetic drive means. The principle of the operation of the camera module will be briefly described. When the coil in the electromagnetic drive means is not energized, the spring member holds the lens at the initial position. When the drive current is supplied from a power supply to the coil in the electromagnetic drive means, an electromagnetic force against the urging force of the spring member is produced and the coil moves along the optical axis direction integrally with the lens. Thus, an automatic focusing operation to move the lens to a desired position on the optical axis can be performed by the control means controlling the magnitude of the drive current.